diff --git a/functions/basic_markets.lua b/functions/basic_markets.lua
index ba7ce0d6..7b3a5e27 100644
--- a/functions/basic_markets.lua
+++ b/functions/basic_markets.lua
@@ -179,9 +179,8 @@ function random_type_market(surface, position, rarity)
 	if #items > 0 then table.shuffle_table(items) end
 	local market = surface.create_entity({name = "market", position = position})
 	for i = 1, math.random(4, 10), 1 do
-		if items[i] then
-			market.add_market_item(items[i])
-		end
+		if not items[i] then break end
+		market.add_market_item(items[i])
 	end
 	return market
 end
diff --git a/modules/wave_defense/biter_rolls.lua b/modules/wave_defense/biter_rolls.lua
new file mode 100644
index 00000000..6142ad60
--- /dev/null
+++ b/modules/wave_defense/biter_rolls.lua
@@ -0,0 +1,67 @@
+function wave_defense_roll_biter_name()
+	local max_chance = 0
+	for k, v in pairs(global.wave_defense.biter_raffle) do
+		max_chance = max_chance + v
+	end
+	local r = math.random(1, max_chance)	
+	local current_chance = 0
+	for k, v in pairs(global.wave_defense.biter_raffle) do
+		current_chance = current_chance + v
+		if r <= current_chance then return k end
+	end
+end
+
+function wave_defense_set_biter_raffle(level)
+	global.wave_defense.biter_raffle = {
+		["small-biter"] = 1000 - level * 2,
+		["small-spitter"] = 1000 - level * 2,
+		["medium-biter"] = level,
+		["medium-spitter"] = level,
+		["big-biter"] = 0,
+		["big-spitter"] = 0,
+		["behemoth-biter"] = 0,
+		["behemoth-spitter"] = 0,
+	}
+	if level > 500 then
+		global.wave_defense.biter_raffle["big-biter"] = (level - 500) * 5
+		global.wave_defense.biter_raffle["big-spitter"] = (level - 500) * 5
+	end
+	if level > 800 then
+		global.wave_defense.biter_raffle["behemoth-biter"] = (level - 800) * 10
+		global.wave_defense.biter_raffle["behemoth-spitter"] = (level - 800) * 10
+	end
+	for k, v in pairs(global.wave_defense.biter_raffle) do
+		if global.wave_defense.biter_raffle[k] < 0 then global.wave_defense.biter_raffle[k] = 0 end
+	end
+end
+
+function wave_defense_roll_worm_name()
+	local max_chance = 0
+	for k, v in pairs(global.wave_defense.worm_raffle) do
+		max_chance = max_chance + v
+	end
+	local r = math.random(1, max_chance)	
+	local current_chance = 0
+	for k, v in pairs(global.wave_defense.worm_raffle) do
+		current_chance = current_chance + v
+		if r <= current_chance then return k end
+	end
+end
+
+function wave_defense_set_worm_raffle(level)
+	global.wave_defense.worm_raffle = {
+		["small-worm-turret"] = 1000 - level * 2,		
+		["medium-worm-turret"] = level,		
+		["big-worm-turret"] = 0,		
+		["behemoth-worm-turret"] = 0,		
+	}
+	if level > 500 then
+		global.wave_defense.worm_raffle["big-worm-turret"] = (level - 500) * 5		
+	end
+	if level > 800 then
+		global.wave_defense.worm_raffle["behemoth-worm-turret"] = (level - 800) * 10		
+	end
+	for k, v in pairs(global.wave_defense.worm_raffle) do
+		if global.wave_defense.worm_raffle[k] < 0 then global.wave_defense.worm_raffle[k] = 0 end
+	end
+end
\ No newline at end of file
diff --git a/modules/wave_defense/main.lua b/modules/wave_defense/main.lua
index 6527c716..90d9d579 100644
--- a/modules/wave_defense/main.lua
+++ b/modules/wave_defense/main.lua
@@ -1,3 +1,5 @@
+require "modules.wave_defense.biter_rolls"
+
 local math_random = math.random
 local threat_values = {
 	["behemoth-biter"] = 10,
@@ -16,43 +18,6 @@ local function debug_print(msg)
 	end
 end
 
-function wave_defense_roll_biter_name()
-	local max_chance = 0
-	for k, v in pairs(global.wave_defense.biter_raffle) do
-		max_chance = max_chance + v
-	end
-	local r = math.random(1, max_chance)	
-	local current_chance = 0
-	for k, v in pairs(global.wave_defense.biter_raffle) do
-		current_chance = current_chance + v
-		if r <= current_chance then return k end
-	end
-end
-
-function wave_defense_set_biter_raffle(level)
-	global.wave_defense.biter_raffle = {
-		["small-biter"] = 1000 - level * 2,
-		["small-spitter"] = 1000 - level * 2,
-		["medium-biter"] = level,
-		["medium-spitter"] = level,
-		["big-biter"] = 0,
-		["big-spitter"] = 0,
-		["behemoth-biter"] = 0,
-		["behemoth-spitter"] = 0,
-	}
-	if level > 500 then
-		global.wave_defense.biter_raffle["big-biter"] = (level - 500) * 5
-		global.wave_defense.biter_raffle["big-spitter"] = (level - 500) * 5
-	end
-	if level > 800 then
-		global.wave_defense.biter_raffle["behemoth-biter"] = (level - 800) * 10
-		global.wave_defense.biter_raffle["behemoth-spitter"] = (level - 800) * 10
-	end
-	for k, v in pairs(global.wave_defense.biter_raffle) do
-		if global.wave_defense.biter_raffle[k] < 0 then global.wave_defense.biter_raffle[k] = 0 end
-	end
-end
-
 local function is_unit_valid(biter)
 	if not biter.entity then debug_print("is_unit_valid - Unit did no longer exist") return false end
 	if not biter.entity.valid then debug_print("is_unit_valid - Unit invalid") return false end
@@ -336,7 +301,7 @@ function reset_wave_defense()
 		unit_groups = {},
 		unit_group_last_command = {},
 		unit_group_command_delay = 3600 * 5,
-		unit_group_command_step_length = 64,
+		unit_group_command_step_length = 96,
 		max_active_unit_groups = 6,
 		max_active_biters = 1024,
 		max_group_size = 256,